A SMF integration hook is a single line of code that calls one or more functions from a list stored in $modSettings. This means that a modder can cause some new code to be run at that point, without changing the core code. It means modders need not worry that some other mod might already have altered the code they want to change. The introduction of integration hooks to SMF has the potential to radically simplify the task of creating and installing many types of mods, and creating bridges to third-party code. Integration hooks are only available in SMF version 2.0 and onwards! A mod's installation package can permanently store its list of hook functions on the database, and specify files to load. A mod can also add integration hook functions from within its code.

Using Integration Hooks

Integration Hooks might seem subtle and mysterious, because it makes the code more dynamic. Anyone reading through the code will have to know the contents of $modSettings in order to know what code is going to be executed at a hook. The concept is simple, though. Just as $modSettings has been used to store all kinds of settings, it is now being used to store the names of functions to execute when an integration hook is called. Most integration hooks appear in the code as a call to call_integration_hook.

function call_integration_hook('name', array(&$param1, &$param2));

Where 'name' is the name of the integration hook, as given in the list below, and the array contains all the parameters to be passed to any integration hook functions that may have been added to the named hook. Because these parameters are passed with the &$ syntax, the parameters are available to be modified by the integration hook functions. In order to take advantage of this, the function definitions must also use the &$ syntax for receiving the parameters

function my_integration_hook_function(&$param1, &$param2){.....}

Before calling each integration hook function, call_integration_hook will check whether that function is callable. If not, it will silently skip that function.

The same function can be added to multiple hooks, but cannot be added more than once to the same hook. It is important to choose unique function names, perhaps by using the Mod name (or an abbreviation) as a prefix, in order to decrease the likelihood that some other mod writer will someday create a function of the same name.

Only one of the integration hooks is not implemented with call_integration_hook. This is the hook 'integrate_pre_load'. This hook simply includes all the files that have been added to the hook.

One of the first mods to take advantage of integration hooks, SlammedDime's SimpleSEF mod, makes only a few edits to the core code, simply to add admin options. The rest of the work is done using integration hooks to load the main SimpleSEF file.

Mod writers would generally do this in an installation script that runs during mod install - like SimpleSEF does. To avoid overwriting any settings already there, use add_integration_function. If it's a one-off thing, use phpMyAdmin and add a new row to, or modify an existing row in the {db_prefix}settings table.

The hook 'integrate_pre_load' is designed to pre-load files containing integration hook function definitions. By adding your file to this hook at install time, you can ensure that all your integration hook functions will be loaded on every page of the forum.

Adding to hooks

add_integration_function

Depending on the $hook_name used, the value of $hook_executes should be either function_name or a file_path. If $make_permanent is TRUE, the change is saved on the database and the $modSettings cache (if caching is used). If $make_permanent is FALSE, no changes are made to the database or the cache.

A modwriter working on a mod called SimplyPerfect might add something like the following to the mod's install.php file:

List of Integration Hooks

So, what are the hooks and how do you use them?

This list documents each of the hooks, what it does, and what it expects as input.

Each hook can be defined and set using the names below. e.g. integrate_pre_include would be referenced in $modSettings as $modSettings['integrate_pre_include'], and managed in the settings table under that name too.

Each integration hook has been described in the following manner:

* Called from: - lists which file it's called from, and at what point the hook will be called on your behalf.

* Purpose: - what the hook is designed for and what it can allow you to do.

* Accepts: - what type of input the hook is expecting. In almost every case this will simply be the name of a function to call, though can be a static method of a class. It should be obvious that the function will need to already be loaded and thus available to SMF already - if not, you may need to ensure integrate_pre_include loads it, the main SMF files contain it, or you otherwise ensure it is loaded.

* Sends: - the list of parameters in order that the hook will be sent from SMF. May be no variables, may be many. If the hook sends variables that you may want to modify before your function ends, make sure your function states it wants the variables by reference.

For example if a hook states that it sends $value1, $value2 and you want to be able to modify those in your function myfunc(), the specification would be:

function myfunc(&$value1, &$value2)

Include files

integrate_admin_include

Called from: Admin.php, just after $admin_areas has been filled and before the call to the #integrate_admin_areas hook.

Purpose: Allows for example loading files that create new admin sections (used by the hook integrate_admin_areas) or more in general loading files that are needed only in the administration section.

Accepts: A string containing a path to a file to load. Certain identifiers can be used which include:

$boarddir translates to the absolute path to your forum, such as /var/www/smf

$sourcedir points to the Sources directory which normally would reside inside SMF's home directory

$themedir points to the directory of the user's current theme

Sends: No parameters, just looks for the file and loads it if found. If the file does not exist, the function silently skips the call and no error is produced.

integrate_pre_include

Called from: Load.php, just after $modSettings has been loaded, which is very, very early on in SMF processing.

Purpose: Allows you to load a single file of PHP source of your own code. Can be used for other integration functions, as it will be loaded on every single page load.

Accepts: A string containing a path to a file to load. Certain identifiers can be used which include:

$boarddir translates to the absolute path to your forum, such as /var/www/smf

$sourcedir points to the Sources directory which normally would reside inside SMF's home directory

Sends: No parameters, just looks for the file and loads it if found. If the file does not exist, the function silently skips the call and no error is produced.

Example: To include a file called MyFile.php in Sources, the syntax would be $sourcedir/MyFile.php.

integrate_theme_include

Called from: Load.php, just after the theme has been initialized and before the call to the #integrate_load_theme hook.

General hooks

integrate_actions

Sends: $actionArray, this is the array containing all the actions provided by SMF. The structure of the array is:

'myaction' => array('ActionFile.php', 'action_function'),

where:

myaction - is the action as it appears in the url (e.g. http://yourforum.tld/forum/index.php?action=myaction)

ActionFile.php - is the file containing the function that is called when the action is requested

action_function - is the name of the function that will be executed

integrate_egg_nog

Called from: ViewQuery.php, before the query log (full page) is built.

Purpose: To be able to add any pre-processing to the query log that may be necessary prior to outputting. Will be of limited use.

Accepts: 1 function name.

Sends: No variables, just calls the function(s) - after verifying the function exists.

integrate_load_theme

Called from: Load.php, at the end of loadTheme(), to load any information that potentially affects top level loading of the theme itself.

Purpose: Designed to modify the layers to be loaded during page generation, for example to avoid calling the 'html' layer if the page is part of a CMS output (where there will already be a similar layer). Orstio expands on it a little more, covering off my initial theory that it was for exporting data to a CMS, rather than its actual use of pulling from.

Accepts: 1 function name.

Sends: No variables, just calls the function - after verifying the function exists.

integrate_load_permissions

Called from: ManagePermissions.php, just after the default permission arrays have been created and populated

integrate_menu_buttons

integrate_output_error

Called from: Errors.php, just after the error itself has been logged but before it has been output to the user.

Purpose: To allow reformatting of the error message, prior to notification to user, or perhaps to log or process in an outside system (e.g. sending an email to administrators on certain types of error occurring)

$error_level - is the PHP error level ident. See the PHP manual for the values this is.

$file - is the filename this occurred in (full server path).

$line - is the line number of the error.

integrate_pre_load

Called from: Load.php, just after $modSettings has been loaded, which is very, very early on in SMF processing - immediately after integrate_pre_include is checked.

Purpose: Allows you to call one or more functions before general SMF processing begins. These can be any defined functions, though it is entirely possible that they are defined in the file loaded by #integrate_pre_include.

Accepts: 1 function name.

Sends: No variables, just calls the function - after verifying the function exists.

integrate_whos_online

Called from: Who.php, if index.php was the loaded page of the user but it's because something else with integration is happening.

Purpose: To be able to add listed actions to Who's Online from integrated apps.

Accepts: 1 function name.

Sends: $actions array from Who.php which will basically be the components of the URL, e.g. index.php?action=page;sa=something results in $actions being array('action' => 'page', 'sa' => 'something') which the integrated function can use to identify what the action really is.

Log in/log out

integrate_login

Called from: LogInOut.php, DoLogIn(), almost first instruction in the function - used during user actively logged in (session exists, more validating that than anything else)
Register.php, Register2(), once registration is completed, just before setting up user cookie - so registration will log them in to both SMF and integrated app

Purpose: To log user in on both integrated code and in SMF at the same time.

Accepts: 1 function name.

Sends: three variables: string of user's username, string of password (hashed) or null if not supplied, length of cookie lifetime in minutes

integrate_logout

Called from: LogInOut.php, LogOut(), if the user is not a guest, after unsetting some session variables, but before clearing their entry in {db_prefix}log_online. They are, technically, still listed as online when the hook is called.

Purpose: To initiate logout in integrated code.

Accepts: 1 function name.

Sends: string representing user's name

integrate_reset_pass

Called from: Lots of places
Profile-Modify.php, authentication(), just before a new password is hashed and about to be inserted into the database (user modifying own password, I think)
Profile.php, ModifyProfile(), for admin modifying another user's password (I think)
Reminder.php, setPassword2(), for when a user resets their password from reminder email
Reminder.php, SecretAnswer2(), for when a user successfully posts their secret answer
Subs-Auth.php, resetPassword(), for when user has forgotten their password and a new one is emailed to them.

Purpose: For notifying external code when a user's password is modified outside of registration.

Accepts: 1 function name.

Sends: $old_user, $user, $newPassword

$old_user - frequently the same as $user, in some cases it can be an unsanitised version of the username

$user - the user name

$newPassword - the newly set password, from whatever source

integrate_validate_login

Called from: LogInOut.php, Login2(), just before actually calling for the user's record in the database.

Purpose: To validate credentials in an external data source as well as with SMF.

Accepts: 1 function name.

Sends: three variables: string of user's username, string of password (hashed) or null if not supplied, length of cookie lifetime in minutes

Unlike other functions, this hook explicitly requires a return value - not all other hook functions handle return values. The return value is a string - either "retry" if there was an issue and user needs to try again, or anything else if the hooked function does not have an issue with the supplied details.

integrate_verify_password

Called from: multiple places
Profile.php, ModifyProfile(), to ensure password is valid before modifying profile details that require password confirmation.
Security.php, validateSession() twice - once, to ensure password is valid during a regular check, and once to ensure adminstrator's password is correct (i.e. even though we were logged in, we need to reauthenticate e.g. admin panel)

Purpose: To run any further tests to validate the user supplied password.

Accepts: 1 function name.

Sends: two variables, representing user name and current unhashed password.

Unlike other functions, this hook explicitly requires a return value - not all other hook functions handle return values. The return value is either exactly identical to true if acceptable, or anything else is a fail.

integrate_verify_user

Called from: Load.php, loadUserSettings(), as the first option.

Purpose: To attempt to log in from external app first, by reusing login credentials; this is taken in preference to either cookie or session details.

Accepts: 1 function name.

Sends: No variables, just calls the function - after verifying the function exists.

Unlike other functions, this hook explicitly requires a return value - few other hook functions handle return values. The return value is cast to an integer to represent user id; 0 = not logged in and to refer to cookie then session, otherwise it represents the user id.

Registration, and other user hooks

integrate_activate

Called from: Multiple places.

ManageMembers.php - during admin approval of members, immediately after approving a member

Profile-Actions.php - activating an account through the profile area

Register.php - activating an account from member activation, immediately after sending the message and immediately before actioning it.

Purpose: To ensure a member is activated in a separate system when activated in SMF itself.

Accepts: 1 function name.

Sends: string representing the member's name (since that is guaranteed to be consistent, member id is not)

integrate_change_member_data

Called from: Subs.php, updateMemberData(), immediately before processing to add to SMF's own tables.

Purpose: To ensure data is migrated to an external system as well as updating SMF's own tables.

Accepts: 1 function name.

Sends: $member_names, $var, $data[$var]

$member_names - an array of the names of members

$var - name of the variable being updated

$data[$var] - the new value

NOTE: Not all values are exported through this hook. Only the following will be exported - any other values updated will not.

'time_format' - the user's time format string for their own time format

'time_offset' - the user's own time offset (from profile)

'avatar' - gallery or URL specified avatar

'lngfile' - user's language

integrate_delete_member

Called from: Subs-Members.php, deleteMembers(), immediately before logging that the action has been done (which is before the SMF tables are all updated)

Purpose: To ensure that the external app is updated when a user's account is removed.

Accepts: 1 function name.

Sends: Number representing user id being deleted from SMF tables.

integrate_register

Called from: Subs-Members.php, just before a user is physically added to the members table. (Same route runs whether it is a conventional user signup or from the admin panel) Validation on details has been carried out by this time.

Purpose: Could be used to do further validation of a user, e.g. an external lookup service or other system that the user accounts are linked to. Alternatively could be used to export user details to an external app and sign them up at the same time.

Accepts: 1 function name.

Sends: $regOptions, $theme_vars$regOptions is a complex array variable. While the full list is in Subs-Members, the most pertinent for most cases are:

Posting and Personal Messages

integrate_bbc_buttons

Called from: Subs-Editor.php, during create_control_richedit(), just after the $context['bbc_tags'] array has been filled with the information regarding bbcode buttons.

Purpose: allows modify the appearance of the bbcode buttons in the rich editor (i.e. the editor with all the controls)

Accepts: 1 function name.

Sends: $context['bbc_tags']

integrate_bbc_codes

Called from: Subs.php, after all the information regarding the default bbcode tags are loaded in the $codes array

Purpose: allows easily add or remove or change the behaviour of bbcode tags.

Accepts: 1 function name.

Sends: $codes

integrate_create_topic

Called from: Subs-Post.php, if a post creates a new topic, once all other SMF processing has been done (like stats updates)

Purpose: Allows you to add topics to a CMS once they are posted. It would likely be better for something such as the Twitter mod to use this as a point to call, rather than modifying the code itself.

Accepts: 1 function name.

Sends: $msgOptions, $topicOptions, $posterOptions - the same three variables used to actually create a topic (see the Function Database for createPost for more), once the changes have been applied, so $topicOptions['id'] is the topic's id, $msgOptions['id'] is the id of its message, for example.

integrate_outgoing_email

Called from: Subs-Post.php, once an email has been assembled, just before it is inserted into the master email queue.

Purpose: Allows you to process or otherwise do something with any email before it is actually sent out.

Accepts: 1 function name.

Sends: $subject, $message, $headers

$subject - listing the email's subject

$message - its main message

$headers - the headers (which includes who it's to, who it's from, date, return path and other things)

integrate_personal_message

Called from: Subs-Post.php, sendpm() once the post is sanitized.

Purpose: To allow you to send or otherwise preprocess personal messages, you could export them to a third party CMS or similar.

Accepts: 1 function name.

Sends: $recipients, $from['username'], $subject, $message

$recipients - an array containing potentially two elements, 'to' and 'bcc', each of which will be an array of membernames that the message is going to

$from['username'] - the username sending the message

$subject - PM's subject

$message - message body

Profile

integrate_profile_areas

Called from: Profile.php, just after the definition of the default profile areas (i.e. the menu entries for the profile section)

Purpose: allows add or modify the menu in the profile area

Accepts: 1 function name.

Sends: $profile_areas

Admin panel

integrate_admin_areas

Called from: Admin.php, during AdminMain(), immediately after the default SMF admin areas have been defined.

Purpose: To allow code to modify the admin menu, adding or removing areas, sections or subsections from it.

Accepts: 1 function name.

Sends: $admin_areas that is the array of admin areas.

integrate_core_features

Called from ManageSettings.php at the beginning of the function ModifyCoreFeatures, just after the $core_features has been populated with the default SMF's Core Features.

Purpose Allows adding new features to the Core Features list in the administration panel.

Accepts 1 function name

Sends $core_features

integrate_general_mod_settings

Called from: ManageSettings.php, at the beginning of the function ModifyGeneralModSettings

integrate_modify_modifications

Sends: $subActions, an array where the key is the subaction and the value is the name of the function to be called for the corresponding subaction

$subActions = array(
'general' => 'ModifyGeneralModSettings',
);

To add a new subaction a mod using this hook should contain:

$subActions['mysubaction'] = 'mysubaction_function';

Internal functions

integrate_buffer

Called from: Subs.php, during obExit, used to add functions to be run on the content prior to it being sent to the user, in the spirit of last-minute widespread content changes.

Purpose: To allow you to modify the content globally before sending to the user, for example SimpleSEF uses this hook to actually replace links.

Accepts: 1 function name.

Sends: $buffer, a string representing the page as a whole.

Unlike other functions, this hook explicitly requires a return value - not all other hook functions handle return values. The return value is the buffer contents.

integrate_exit

Called from: Subs.php, during obExit, used when finally leaving the theme system either in the event of normal execution or fatal errors (i.e. any time a full page is generated that isn't a redirect/attachment)

Purpose: To allow you to do final shutdown on external apps, close connections, free resources. Can also be used with portals or other output handling functions.

Accepts: 1 function name.

Sends: boolean value whether the footer should be output (i.e. footer should be done and not in wireless template)

integrate_fix_url

Called from: News.php, during fix_possible_url().

Purpose: To allow the RSS feeds to have adjustments made for queryless style URLs - and any other URL changes that may be required.

Accepts: 1 function name.

Sends: $val, the original URL

integrate_magic_quotes

This one isn't actually a function, it's a setting that's relevant. PHP's idea of magic quoting is one of the most irritating ideas it has ever had, to attempt to automatically be able to quote values that are incoming from userland. Unfortunately its behavior is somewhat unpredictable and therefore unreliable.

In the process of sanitizing $_GET, SMF does its own clean-up of magic quotes, handling the various types that may be incoming, but other systems do not do this and rely on default PHP behavior. This setting overrides SMF's behavior and returns it to the default.